A. Field of the Invention
The field of the present invention relates generally to devices and systems for electronically monitoring ingress and egress through a passageway, such as door openings and the like. More particularly, the present invention relates to such devices and systems wherein the interruption of a beam of radiation, such as a beam of infrared energy, activates an alarm signal or causes other action upon the entry or exit of a person through the passageway. Even more particularly, the present invention relates to such devices and systems that are specially configured as an alarm for a passageway leading to a pool or other potentially dangerous area.
B. Background
In general, devices and systems for the detection of persons, pets or other objects through a passageway are well known in the art. Such devices and systems are typically utilized to prevent unauthorized entry into a restricted area or unauthorized exit from a safe or otherwise controlled area. For purposes of the present invention, the term “passageway” includes a doorway, window, gate and any other type of opening which is defined by a pair of opposing and spaced apart sidewalls through which a person, pet or other object may pass. Typically, but not exclusively, passageways are defined by a frame, such as a door frame or window sill, that includes the opposing sidewalls and at least a top wall. Although the opposing sidewalls are usually configured to be generally vertical, the term “passageway” is not limited to vertical sidewalls and includes sidewalls that may deviate quite substantially from a vertical orientation. As well known in the art, a home, business or other building may have a number of passageways, including the front door, rear door, side door and windows. Generally, one or more of the building's passageways are selected to be monitored by an ingress/egress monitoring system.
The area for which ingress or egress into or out of is desired to be monitored can be any type of area, whether it is located inside a building or outside of a building. Often, the entry into or exit from the area is restricted to certain persons or certain types of persons so as to protect those who are inside the building from unauthorized entry by others or to determine when a person inside the building exits out of the building without authorization. One example of the use of such monitoring systems is an alarm system that detects the entry of unauthorized persons into a home, office or other structure. Another example of the use of such monitoring systems is an alarm system that detects when a person exits the structure through a passageway when he or she is not allowed to exit, such as an alarm system connected to the rear or emergency door of a store or the like. There is a wide variety of different configurations of such alarm systems that utilized various detection and alarm devices. Generally, however, a common feature of these types of alarm systems is that they are configured to detect the unauthorized ingress or egress of any person who passes through the passageway without first deactivating the alarm system. Some of these alarm systems utilize the unauthorized opening of a door or window to indicate a person passing through the passageway and the activation of the alarm. Other alarm systems utilize the direct movement of a person or other object through the passageway, usually detected by a motion detector or by breaking an invisible beam of light or other radiation, to determine unauthorized ingress or egress and cause the alarm to activate.
One type of alarm system which utilizes the movement of a door to indicate unauthorized passage through the passageway that is secured by the door comprises a pair of cooperating magnets which are connected to a control panel having an alarm. One of the magnets is placed on the non-moving frame around the door and the other magnet is placed in cooperating relation on the door such that when the door is closed the magnets are disposed next to each other and the alarm is silent. Opening the door displaces the door magnet from the frame magnet and causes the control panel to activate the alarm. Often, this type of alarm system is provided with a delay circuit such that the alarm does not sound for a preset amount of time. The alarm can be deactivated when the threat no longer exists or has passed. Typically, these alarms are provided with a pass through feature allowing a person to enter a code, push a button or perform some other task to prevent the alarm from sounding. Another type of alarm system that utilizes the opening of a door to activate an alarm is the type that operates in conjunction with the mechanism which opens the door, such as an emergency exit bar. If the alarm system is not deactivated, an alarm will sound when a person utilizes the opening mechanism. Many of these types of alarm systems utilize a mechanical activation mechanism to sound the alarm. The emergency exit bar of U.S. Pat. No. 5,517,176 to Lavell, et al. utilizes an infrared beam that is directed along the front of the exit bar. Interruption of the beam causes the alarm to sound. A number of other types of alarm systems utilize the opening of a door or window to sound an alarm.
There are a number of alarm systems that do not depend on the opening of a door or window to indicate that an unauthorized person is passing through the passageway to activate an alarm. One common type alarm system utilizes a beam of infrared energy transmitted across the passageway and the interruption of that beam to indicate that a person or other object is passing through the passageway. Typically, such alarm systems comprise an infrared transmitter on one side of the passageway and an infrared receiver on the opposite side of the passageway, with the beam of infrared energy transmitted between the transmitter and receiver. The infrared transmitter and receivers are usually mounted on or into the opposing sidewalls that define the passageway, such as on or in a door frame which supports a door. Examples of such systems are shown in U.S. Pat. No. 4,516,115 to Frigon, et al. and U.S. Pat. No. 6,255,946 to Kim. Infrared transmission and reflection are also utilized in garage door openings to indicate the presence of a person or object in the passageway who could be injured or which could be damaged by the closing of an automatic garage door. If the infrared beam is broken by a person or object, the downward movement of the garage door will stop and, typically, reverse direction to avoid injuring the person or damaging the object. Examples of such systems are shown in U.S. Pat. No. 4,922,168 to Waggamon, et al. and U.S. Pat. No. 5,656,900 to Michel, et al. Infrared beam transmission laterally across an open passageway is also utilized to detect movement of a person through the passageway, turn on lights or other devices inside a room in which a person has entered by passing through the passageway and then turn off such devices when the person exits the room and for similar monitoring uses. Often, these devices are configured with more than one infrared transmitter/receiver combination so the system can determine whether one or more people have entered the room and when the last person leaves the room and/or are configured to determine the direction the person is moving (i.e., in or out of the room). For such uses, the infrared transmitters/receivers are placed in side-by-side relation to indicate in and out movement through the passageway. Examples of such systems are shown in U.S. Pat. No. 4,719,363 to Gallacher and U.S. Pat. No. 6,255,946 to Kim.
One area that is commonly restricted to selective persons is a backyard pool. As well known, unfortunately, many drowning deaths occur each year due to a small child entering the pool area of a home when he or she is not authorized to be there, resulting in the child falling or otherwise entering the pool without supervision by an adult or other responsible person. Many municipalities have barrier code requirements that are intended to physically keep a child from entering the pool and/or sound an alarm if a child enters the pool without the alarm being deactivated. Many people utilize a fence around the pool to keep a child from the pool, with a gate having a locking mechanism to allow authorized persons to enter the pool area. Various pool alarms are also available for above-ground and in-ground pools that sound an alarm when someone enters the water. Examples of such alarms are the Poolguard® Inground Pool Alarm and the Poolguard® Above Ground Pool Alarm available from PBM Industries, Inc. This company also sells a Poolguard® Door Alarm that is of the type described above which utilizes a pair of adjacent magnets to activate an alarm upon the opening of a door that, for use with their product, leads to a pool area.
One problem with the presently available pool alarm systems is that they are activated in response to the activity which sets off the alarm, such as a door opening, motion in the pool or a person walking through the door, regardless of whether the person causing the activity is a child or not. As is well known, it is generally not necessary to have an alarm system for most people who are likely to utilize the pool, such as adults and older children. The need and primary use of such alarm systems is to protect younger children who are not likely to know how to swim or do not swim well enough to be left on their own around or in the pool. As a result, most prior art pool alarm systems, whether they operate at the door, gate or in the pool, have a mechanism that allows adults and older children to pass through to the pool without activating the alarm. Such mechanisms are particularly useful when there is a number of people, some of whom are younger children, who will be moving between the inside of the house and the pool located outside the house, such as will occur during a party or the like. Unfortunately, it is somewhat common for the pool alarm system to become annoying to adults or older children, who tend to get frustrated with the need to bypass the alarm system every time they want to go outside the house. In addition, often a person in a house desires to leave open a door, which may lead to a pool, as he or she passes through the door carrying items between the house and pool or to take advantage of a breeze. As a result, these alarm systems often get turned off or otherwise not utilized. The rationale usually is that the young child who needs protecting either knows better than to go outside or he or she can be sufficiently watched to ensure they stay inside. The result of such assumptions can be tragic. If an alarm system could distinguish between a child walking through the door or other passageway leading to a pool and an adult or older child who walks through that passageway, then the alarm system could be left on all of the time to protect against drownings.
As also well known, pools are not the only dangerous area around a home or other building for young children. A child can be injured or killed if he or she runs out of the house and enters the street in front of a house, follows a person to their car in the driveway or climbs on equipment or materials that are stored along the side of the house, among other potentially dangerous activity. Often the child will be able to access the dangerous area because the door is intentionally left open for an adult or older child to pass through as he or she is carrying groceries or other items, to take advantage of a breeze or while waiting for someone to approach the building or because the door is unintentionally left open due to carelessness or faulty operation of the door closing mechanism. As with pool alarms, if an alarm system could distinguish between small children and adults or older children passing through a door or other passageway, then it could be utilized at any passageway that leads to a potentially dangerous area and be kept in the alarm mode all of the time.
What is needed, therefore, is an improved alarm system that is configured to activate an alarm or cause other action when a person or an object of a certain height passes through a passageway but does not activate the alarm or cause the other action when a person or an object of a different height passes through the passageway. For use as a pool alarm system, the alarm system should be configured to activate an alarm, preferably an audible alarm, when a child passes through a passageway that leads to a pool, but not activate the alarm when an adult or an older child passes through the passageway. The alarm system must be able to effectively and quickly distinguish between a small child and an adult or older child to determine if an alarm should sound to warn persons that a child has exited a safe area and entered a potentially dangerous area, such as a pool or the like. Such an alarm system should be configured to operate in any type of passageway, whether the passageway is defined by a door frame or not. Preferably, the alarm system should be relatively simple to install, easy to operate and inexpensive to manufacture.